really i tink for OPT there should be iron and copper, one day i have to go parallel GM70 SEP with the big Hammond OPT1642SE,
75watts 5,000ohm 300 ma. 53 Henrys
but need a super IT for 211 driver
http://w2dtc.com/w2dtc-homebrew-hi-fi-am-driver-transmitter/2006-0920-hammond-1642se.jpg
75watts 5,000ohm 300 ma. 53 Henrys
but need a super IT for 211 driver
http://w2dtc.com/w2dtc-homebrew-hi-fi-am-driver-transmitter/2006-0920-hammond-1642se.jpg
Did you go with Jacks standard SE or the low IMD?
Whats your operating points, voltage?
I was thinking about a custom from Jack 40W-7K-100ma
Current Operating point is 90ma @ 1100v using a Hammond 6.5K (1629SEA)
I had a pair of those recently and sold them after realizing the size and complexity of the power supply. You might as well build using an 833C because thats your next step after parallel......
I do have an extra pair of Hammond 1638SEA but thought my operating point of 88ma was a bit high, I was saving it for a possible 211 or 845 output.
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They were standard at the time about six or seven years ago when originally ordered. It took me a year to decide to complete the amplifiers after I got cold feet half way through. I ended up designing unregulated solid state supplies for them to keep the cost down in the event of failure.
I'm using them with only minor modifications since they were finished and took what I learned and applied it some new designs over the past couple of years.
After much agonizing I choose a load line intended to reduce distortion rather than maximize power. I'm running at 1kV, 90 - 120mA depending on tubes. Transformer is 7K:8/150mA/40W. The secondary is copper. I get about 20Wrms out at 2%, no feedback is employed. It's really rather inefficient, but sounds good so I don't worry too much about the heat which is considerable.
I'm using them with only minor modifications since they were finished and took what I learned and applied it some new designs over the past couple of years.
After much agonizing I choose a load line intended to reduce distortion rather than maximize power. I'm running at 1kV, 90 - 120mA depending on tubes. Transformer is 7K:8/150mA/40W. The secondary is copper. I get about 20Wrms out at 2%, no feedback is employed. It's really rather inefficient, but sounds good so I don't worry too much about the heat which is considerable.
just back to my personal GM70 SET, change plate choke to cathode choke and
negative bias for 6L6 (6P3S-E) and GM70 and rectifier 816 MOV to replace 866A
much more color and beatyfull music
i do not need much power so preamplifier its an option for full power
negative bias for 6L6 (6P3S-E) and GM70 and rectifier 816 MOV to replace 866A
much more color and beatyfull music
i do not need much power so preamplifier its an option for full power
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these are 816 its smaller but no problem psu 280mA 950V
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OK, I believed that were 866 junior, as they are known here (Thinner than 866's).
Congratulations for your job.
Congratulations for your job.
Do you guys have any idea of the lifespan of these rectifiers? I have the DCG4/1000 made by RTC and I run them in a C.T configuration at 110mA with a choke input filter. Startup delay is respected every time I turn on the amplifier.
several years ago, I had an 80/40/20 mts ham radio transmitter (AM, now prohibited) 2 807 * 2 1625's class AB2, that had 866's junior as the main rectifiers. I loved to use them as a kind of "VU meters", ja ja ja....
MOV should vaporize mercury before HT come on, also first time and each time they moove let tubes preheathing 20'
RCA problem see jpg
otherwise these are a the same time fragile and everlasting
the beatyfull glow demand minimum 0.2A HT better more and more
or small 816 glow easy
sorry for the bad english
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